In Azure's traffic manager, I am doing some testing with TWO failover URLs: Two different endpoints are configured for the traffic manager (failover1.mysite.com, failover2.mysite.com.), however, my local browser (Chrome for example) seems to be caching the DNS record on its own and redirecting to what it thinks is still the destination, rather than letter Azure Traffic Manager re-route. Trying the request in a new browser or Incognito session will result in the request reaching the correct site. But for existing sessions, failover updates are not being registered and still hitting the site we are trying to redirect traffic away from. Does anyone have any experience with this?
How does Azure Traffic Manager reduce latency? It chooses only the fastest networks between endpoints. It chooses the endpoint that's closest to the user's DNS server. It caches content, similar to how content delivery networks work.
Traffic Manager is a DNS-based traffic load balancer that enables you to distribute traffic optimally to services across global Azure regions, while providing high availability and responsiveness. Because Traffic Manager is a DNS-based load-balancing service, it load balances only at the domain level.
Traffic Manager uses the round-robin, performance, or failover method to decide to which endpoint to route traffic. CDNs serve cached content directly from CDN nodes that are closest to end users. CDNs can reduce traffic to original service nodes by serving static content directly.
Traffic Manager is not a proxy or a gateway. Traffic Manager does not see the traffic passing between the client and the service.
I had the same issue while I was dealing with Azure Traffic Manager or AWS CloudFront.
DNS Record is associated with its TTL value. It is not something wrong with the Azure Traffic Manager. It is the TTL value that is letting the DNS client to cache the IP address.
How to check TTL value of DNS:
If you are using Windows,
https://support.rackspace.com/how-to/nslookup-checking-dns-records-on-windows/
If you are using linux follow the detailed instructions here,
https://www.cyberciti.biz/faq/howto-use-dig-to-find-dns-time-to-live-ttl-values/
Hope it helps.
From Microsoft's overview of their load balancing services:
Traffic Manager is a DNS-based traffic load balancer [...] it load balances only at the domain level. For that reason, it can't fail over as quickly as Front Door, because of common challenges around DNS caching and systems not honoring DNS TTLs.
With Front Door you can route requests to different backends based on rules and/or the health of the backends themselves so it doesn't have the issue you describe.
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